Cold Weather Hydraulic Weakness in the Ford New Holland 655C

[MikePhua]

The 655C’s Role in Utility and Agricultural Work
The Ford New Holland 655C backhoe loader was introduced in the early 1990s as part of a broader push to modernize compact construction equipment. Built under the New Holland brand after Ford’s merger with Fiat, the 655C was designed for versatility in both agricultural and municipal applications. With a diesel engine producing around 85 horsepower and a hydraulic system capable of powering a front loader and backhoe simultaneously, it became a popular choice for small contractors and landowners.
Thousands of units were sold across North America and Europe, particularly in regions where rugged terrain and seasonal weather demanded reliable performance. However, like many machines of its era, the 655C’s hydraulic system can exhibit performance issues in colder temperatures—especially when fluid levels or viscosity aren’t properly managed.
Symptoms of Hydraulic Weakness in Cold Conditions
Operators report that in near-freezing temperatures (around 0°C or 32°F), the front loader struggles to lift beyond 1.5 meters, and the crowd cylinder retracts with a jerky, trembling motion. Extension appears normal, but retraction is hesitant. Additionally, unusual noises may emanate from the loader valve or hydraulic filter area, suggesting cavitation or air entrapment.
Interestingly, the boom cylinder often continues to function normally, indicating that the issue is localized to specific circuits or components rather than a total system failure.
Common symptoms include:

• Reduced lifting capacity
  
• Jerky or hesitant cylinder movement
  
• Foaming hydraulic fluid
  
• Audible whining or gurgling from valves or filters
  

These symptoms tend to disappear once ambient temperatures rise above 10°C (50°F), suggesting a strong correlation between fluid behavior and thermal conditions.
Hydraulic Fluid Behavior in Cold Weather
Hydraulic oil thickens as temperatures drop, increasing resistance within the system and reducing flow rates. This can lead to delayed response, pressure drops, and cavitation—where vapor bubbles form and collapse within the fluid, causing noise and potential damage.
In the 655C, the hydraulic system relies on an open-center configuration, meaning fluid continuously circulates until a valve is actuated. When fluid is too viscous, it struggles to circulate efficiently, especially through filters and narrow passages.
Foaming is another concern. If fluid levels are low, the pump may draw air into the system, creating bubbles that reduce pressure and cause erratic movement. Foamy oil also appears creamy or milky, which can be mistaken for water contamination.
Diagnosing and Resolving the Issue
In one case, the operator initially suspected water contamination due to the creamy appearance of the oil. However, upon closer inspection, it became clear that the fluid was simply foaming due to low levels. After topping off the reservoir, the system returned to normal operation, and the noises ceased.
Recommended diagnostic steps:

• Check hydraulic fluid level with the engine off and cylinders retracted
  
• Inspect fluid for foaming or discoloration
  
• Listen for air bubbles passing through the system during startup
  
• Monitor cylinder behavior during extension and retraction
  

If fluid is low, topping off with the correct specification oil (typically ISO 46 or ISO 68 depending on climate) can resolve the issue. In colder regions, switching to a lower-viscosity oil like ISO 32 may improve cold-start performance.
Impact of System Modifications
Adding new hydraulic components, such as an extendable dipper stick cylinder, increases the system’s fluid volume requirements. If the reservoir isn’t topped off after installation, the system may run dry during operation, leading to foaming and pressure loss.
One operator noted that after installing a new cylinder, he failed to add additional oil, which likely caused the initial symptoms. Once corrected, the machine operated normally even in cold weather.
Preventive Measures for Cold Climate Operation
To ensure reliable hydraulic performance in low temperatures, operators should consider the following:

• Use winter-grade hydraulic oil with appropriate viscosity
  
• Store the machine indoors or use engine and hydraulic warmers
  
• Allow the machine to idle for several minutes before engaging hydraulics
  
• Check fluid levels regularly, especially after component replacement
  
• Replace filters annually to prevent flow restriction
  

In extreme climates, installing a hydraulic tank heater or using synthetic hydraulic fluid can further reduce cold-start issues.
Conclusion
The Ford New Holland 655C remains a dependable backhoe loader, but its hydraulic system requires careful attention in cold weather. Weak performance at low temperatures is often a symptom of low fluid levels, increased viscosity, or recent system modifications. By understanding the behavior of hydraulic oil and maintaining proper fluid levels, operators can avoid downtime and extend the life of their equipment.
In the world of utility machines, cold weather doesn’t have to mean cold hydraulics—just a bit of preparation and a watchful eye.